This is an R03 grant application for two years of funding to apply novel advanced image analysis techniques and introducing technology that would improve the placement of the Radiofrequency (RF) electrode during CT-guided guided RF ablation. This application qualifies as an R03 because it is a small research project that can be carried out in a short time with limited resources, as only retrospective data will be analyzed. The knowledge obtained from this study will establish the feasibility of registering pre-procedural high resolution images with intra-procedural images. Pre-procedural acquired data enables accurate identification of tumor margin and delineates critical tissue to preserve. However, currently, the alignment of pre- and intra-procedural data is done mentally by interventional oncologists. Clinical studies have shown that tumors smaller than 3 cm are often treated completely with RF ablation. Nevertheless, non-rigid motion of the abdominal anatomical structures can create difficulties in accurately assessing the RF electrode placement, considering the small size of treated tumors. Currently there is no method for fusing pre and intra-procedural data during RF ablations. A retrospective analysis of data available at BWH will be performed in this pilot study. Pre- and intra- procedural images will be both rigid and non-rigid registered. We will evaluate if pre-procedural images can be registered to intra-procedural images and delineate better the time for targeting. Since post-procedural images do not contain visible tumor, whether the tumor was completely treated, the assessment is often difficult to determine. We aim also improving the quantitative assessment of the treatment outcome by registration of pre-and post-procedural images. The success will be determined by the accuracy and robustness of the registration results obtained. Both mathematical methods and visual inspection by radiologists of results will be employed in assessing the results. This proposal will benefit public health by developing and assessing key technologies to enable enhanced navigation during the image guided radiofrequency ablation. The capacity to visualize the tumor and tumor margin throughout the procedure will better enable the interventional radiologists to achieve accurate RF electrode placement and coagulation necrosis for the entire tumor mass, without unexpected site effects. [unreadable] [unreadable] [unreadable]